Approximately 1/3 of opioid addicts are women of child-bearing age. Pregnancy during opioid dependence presents a complex array of therapeutic challenges. Methadone is the only maintenance pharmacotherapy recommended for use in pregnant opioid-dependent women. Methadone offers many benefits relative to continued untreated heroin addiction or medical detoxification, but it also has medical complications. Compared to non-drug exposed infants, opioid exposed infants have longer and more costly neonatal hospitalizations and display neurophysical and behavioral disruption. It is estimated that 55 percent-94 percent of infants exposed to opioids in utero will show signs of opioid withdrawal. Buprenorphine offers the potential of providing benefits comparable to methadone with fewer medical problems. Buprenorphine is reported to produce only a mild abstinence syndrome following abrupt withdrawal. Its potential will be assessed in a randomized controlled clinical trial comparing methadone and buprenorphine in this special population. Results will be compared to opiate dependent controls who choose nonpharmacological treatment. This comprehensive interdisciplinary effort will be conducted in the Center for Addiction of Pregnancy. Subjects randomized to equivalent optimal doses of methadone (N=35) or buprenorphine (N=35) will be followed through pregnancy and compared to nonpharmacologically treated (N=35) subjects. Primary outcome measures are: neonatal abstinence symptoms and length (days) of hospital stay. Secondary fetal/neonatal outcome measures are: standard antenatal measures, NICU Network Neurobehavioral Scale, fetal growth ratio, total anti-withdrawal medication given, infant cry behavior and physical birth parameters. Secondary maternal outcome measures include: treatment retention, objective and subjective measures o drug use, global assessments, dose adequacy and safety data. Additionally, mother and infant pharmacokinetic data will be collected to aid in interpretation of outcomes. The study will provide critical clinical data comparing the neonatal abstinence syndrome and safety/efficacy of methadone and buprenorphine in the mother and infant pre- and postpartum using rigorous scientific methodology.